The long-term objective of this research is to gain better understanding of the neural foundation of perception and memory. It is designed to provide new data concerning the processes by which the brain of the primate encodes, retains, and utilizes spatial information in behavior. The rationale is based on suggestive evidence that the posterior parietal cortex, in man and monkey, is the cortical substrate for spatial representation, a kind of dynamic neural map of extrapersonal space. The work will be conducted on macaques (Macaca mulatta). Some of the animals will be trained to distinguish objects by touch and to remember their shape for later recognition. The posterior parietal cortex will be cooled with implanted probes to test the effects of the reversible functional depression of that cortex on tactile (haptic) and crossmodal (haptic/visual) recognition performance. Nerve-cell activity will be investigated in the posterior parietal cortex while the monkey is engaged in those forms of performance; the principal aim is to determine the organization of cortical neurons representing stereognostic information. Other animals will be trained to distinguish and remember colored stimuli indicating the position of reward in the immediate space and future. The functional interactions between parietal and prefrontal cortex will be explored in these animals with a combination of cryogenic and microelectrode recording methods. The effects of cooling one cortical region on the neuronal activity in the other region will be analyzed, as will be the effects of cortical cooling on behavioral performance; the aim is to clarify the role of the normal interactions between the two cortices, presumably mediated by direct connections, in the spatial organization of behavior. Computer methds will be used for analyzing the effects of cryogenic depression as well as the patterns of neuronal discharge in task performance. The results of these experiments may help to elucidate the pathogenesis of disorders of the cerebral cortex in the human and to develop remedial measures for such disorders.